1. Field of the Invention
The present invention relates generally to terminal connectors. More particularly, the present invention relates to a method for attaching a terminal connector to a metallic surface by friction joining.
2. Disclosure Information
Practically all automotive vehicles produced today have front and rear glass windshields. It is common practice to provide one or both of such windshields with a wire circuit either attached to or embedded within the windshield. These wire circuits may be used for a variety of purposes, such as an antennae for sending/receiving radio frequency signals, a high resistance windshield defroster circuit, and so forth, as illustrated in FIG. 1. Here, the windshield 80 has a wire circuit 82 attached thereto, with each end of the circuit having a termination 84. Typically, each termination 84 has a metal clip-like connector 86 attached thereto, with a mating external circuit connector 88 being attached to the clip connector 86. The external circuit 90 in turn may be connected to a radio, a theft prevention/detection system, a keyless entry system, a cellular phone, a power circuit for defrosting the windshield, etc.
The typical method used to attach the metal connector 86 to the glass windshield 80 involves the following steps. First, a glass particle/silver particle paste or "frit" is deposited onto the windshield adjacent to and in contact with the circuit termination 84. Second, the fritted windshield is fired in an oven such that the glass of the windshield and the glass particles in the frit soften so as to bond to each other. This causes the fired frit deposit--at this point referred to as a "pad"--to bond to the glass, while the silver particles distributed throughout the pad create an electrically conductive path from the termination 84 to the top surface of the pad. Third, a predetermined amount of solder is deposited atop the pad. And fourth, the metal clip connector 86 is placed on the solder and the solder is heated to a temperature well above its melting point and then allowed to cool, so that the clip is soldered to the pad.
However, this approach presents a problem in that the heat used to melt the solder also increases the risk of cracking the adjacent windshield glass. Furthermore, upon cooling from these elevated temperatures, there is a tendency for one or more of the connector, solder, pad, and glass to delaminate and/or debond from each other due to the large differences among their respective coefficients of thermal expansion.
It would be desirable, therefore, to provide a terminal connector and a method for attaching the same to a windshield or other fragile workpiece without subjecting the workpiece to the elevated temperatures presented by previously known processes.